Embodiments of the inventive concept relate generally to data storage devices such as hard disk drives (HDDs). More particularly, embodiments of the inventive concept relate to methods of setting zones in recording media of the data storage devices.
Certain types of data storage devices, including HDDs, store data on rotating disks comprising concentric tracks. In these disks, data is accessed by positioning a read head over a selected track and rotating the disk to a part of the track containing the data.
The tracks of an HDD are generally divided into sectors each comprising a fixed number of bits (e.g., 512 bits). In many conventional HDDs, each track has the same number of sectors. Accordingly, the larger outer tracks store the same number of bits as smaller inner tracks, which results in inefficient utilization of disk space. To address this inefficiency, newer data storage devices, including some HDDs, have adopted a technique known as “zoned bit recording” in which the concentric tracks are divided into groups called “zones”. Each zone comprises tracks having the same number of sectors, but number of sectors-per-track differs from zone to zone. For instance, a zone comprising a group of inner tracks can have a certain number of sectors per track, and a zone comprising a group of outer tracks can have a larger number of sectors per track. By using a larger number of sectors in the tracks of outer zones, the disks can achieve greater bit density and storage capacity in those tracks.
One issue presented by zoned bit recording is that different zone layouts can produce different numbers of bit errors. This occurs because there is generally a tradeoff between bit density and bit error rate. Accordingly, in conjunction with the development of different zone layouts, research is also being conducted on techniques for reducing bit error rate (BER) distributions in different areas of recording media.